Plaster-board lath



May 8, 15928."

0. L.- ROUTT ET AL PLASTER BOARD LATH Filed 06t- 27, 1925 Patented May8, 1%28.

UH'I'EED EQATENT ORVILLE I. RO'UTT AND ROBERT M. GREENIIEAF, OF LOSANGELES, CALIFORNIA, AS- SIGNORS TO PLASTOID PRODUCTS, INC., OF LOSANGELES, CALIFORNIA, A. COR- PORA'IION OF CALIFORNIA.

PLASTER-BOARD LATE.

Application filed October 27, 1925. Serial No. 65,121.

Our invention has among its salient objects to provide an improvedplaster board of the character which includes a plastic matter betweensurface sheets and which has hardened, our improvement consisting in thenature of thedepressions made in the face of the article whereby toroughen the surface sheet and break or fracture the sheet adjacent thedepression whereby to make possible a better bond of the plaster withthe surface sheet. It is known that the plaster applied to these plasterboard lath will adhere to a suitable surface sheet on the board and willadhere to the sheet, particularly when said sheet is roughened or brokenso as to give a rough edge. When this roughened edge is made inconnection with a depression, a very satisfactory plaster board lath isformed. We have shown two forms of our invention, one of said formsbeing made by depressing the paper into the body of the article so as tostretch the paper and slightly break it at the edge of the depression,leaving the edges rough, and being wholly below the plane of the surfacesheet, while the other form of the invention is provided with anincreased bonding surface extending above the plane of said surfacesheet by bunching the surface sheet in spots and stretching it down intothe depression even to the extent of break ing it and leaving its edgesrough.

In order to explain our invention, we have illustrated one practicalembodiment thereof on the accompanying sheet of drawings, which we willnow describe.

Figure 1 is a fragmentary, perspective view of a plaster board lath,embodying our invention;

Figure 2 is a fragmentary sectional view showing one form of depression;and

Figure 3 is a similar view showing the other form of depression with thesurface sheet crimped or bunched at the edge of a depression.

In the drawings, the plaster board lath shown consists of the twosurface sheets, 1 and 2, with the body of plastic matter or compositiontherebetween, which in and of itself is old and forms no part of thisinvention apart from the other features to be described.

. We have discovered that we can form a very efficient plaster lath bymaking depressions into one side of the board after it is formed, suchdepressions being of any desired'form, but made by depressing thesurface sheet down into the body of the material by stretching it andeven to the extent of slightly breaking the sheet at the edges of thedepression so as to leave roughened edges adjacent the depression, saiddepres sion being designated 4, and the roughened edges being designated5, and thus forming means for establishing a holding bond between theplaster board and the coat of plaster to be applied thereto, and formingno protrusions above the plane of the surface sheet, as will be clearfrom Fig. 2 of the drawings.

In Fig. 3, we have shown how the process can be carried a little furtherand by holding the depressing fingers or elements by which thedepressions are formed, the sur face sheet is gathered into bunches atthe edge of the depression, as at 7, being moved sufficiently andstretched down into the depression that said sheet is torn or brokenaway from the body thereof adjacent said depression, as at 6, leavingtwo rough edges of the paper, and the crimped part thereof, and thusgreatly increasing the bonding surface of the article, for when thecrimped or bunched paper hardens and the broken edges become dry andhard, a good bond can be secured between them and the plaster as thelatter is applied thereto.

We do not make the depressions so deep that the surface sheet is torn toany extent in order to expose edges of the composition of which theboard is made, but stretch the paper down into a slight depression andslightly break the paper at one or two edges, substantially in themanner indicated. We have found also that by using depressing fingerswhich will form a depression having converging sides and with the brokenedges converging substantially in the manner indicated, that the coat ofplaster wedges into these angles with a beneficial effect. We do not,however, limit our invention to any particular form of depression,except as we may be limited by the hereto appended claims.

We claim:

1. Plaster board lath of the character referred to having a body ofplastic material with cover sheet and provided with a series ofdepressions 111 which the paper cover sheet is pulled apart to formragged edges to expose the plastic material on an inclined "side 01 saidplaster board lath having a series of concaved depressions formed by ajab to depress the cover sheet into the plastio material, said coversheet being pulled apart at one side of the depression 'with raggededges exposing the plastic material between said ragged edges on aninclined surface below the plane of the surface of said board lath.

3. Plaster board lath having a plurality of depressions made in one facethereof, each depression having its cover sheet pulled apart so as toform ragged edges exposing the body of said board between said raggededges eacli depression also having its cover sheet bunched at theopposite side thereof to form Wrinkles, whereby said ragged edges,exposed body and wrinkled cover sheet form an effective bond Withplaster applied thereto;

Signed at Los Angeles, Los An'geles County, California, thi's'l9 day ofOctober, 1925.

'ORVILLE L. ROUTT. ROBERT M. GREENLEAF.

